Answer: you bought 9 burgers and 16 tacos
Step-by-step explanation:
Let x represent the number of burgers that you bought.
Let y represent the number of tacos that you bought.
You buy a total of 25 burgers and tacos. It means that
x + y = 25
The burgers cost $3.50 each and the tacos cost $2.25 each. The total cost of the burgers and tacos that you bought is $67.50. It means that
3.5x + 2.25y = 67.5- - - - - - - - - - - - 1
Substituting x = 25 - y into 1, it becomes
3.5(25 - y) + 2.25y = 67.5
87.5 - 3.5y + 2.25y = 67.5
- 3.5y + 2.25y = 67.5 - 87.5
- 1.25y = - 20
y = - 20/ - 1.25
y = 16
x = 25 - y = 25 - 16
x = 9
Let the radius of the bigger circle,R = 6cm
Let the radius of the smaller circle, r = 4cm
Area of the shaded region= area of the bigger circle - area of the smaller circle
Area of the smaller circle = πr^2
3.14×4×4 = 3.14×16 = 50.24cm^2
Area of the larger circle = πR^2
3.14×6×6 = 3.14×36 = 113.04cm^2
Therefore area of the shaded region = 113.04 - 50.24 = 62.8cm^2
